Former Central African Republic militia leader Maxime Mokom would be subjected to "detention and torture" if he was to be send back to his troubled homeland, his lawyers said on Friday.
Mokom was released by the International Criminal Court last week, shelving his war crimes case after the prosecutor dropped all charges.
"Mr Mokom unambiguously opposes any return to the Central African Republic by the ICC," his lawyers said.
"The defence has every reason to think that Mr Mokom would be subjected to arbitrary and illegal detention, torture and cruel treatment were he to be forcibly rendered, against his will," his lawyers said in a letter sent to AFP.
Mokom, 44, was released after chief prosecutor Karim Khan said his office concluded there were "no longer any reasonable prospects of conviction at trial even if the charges were confirmed."
He had faced charges of war crimes and crimes against humanity over alleged atrocities committed against Muslim civilians in the CAR, a former French colony, by his self-proclaimed self-defence militias in 2013 and 2014.
One of the world's poorest countries, the CAR was plunged into bloody sectarian conflict after Seleka rebels, a coalition of armed groups mainly composed of Muslims, ousted president Francois Bozize in early 2013.
Mokom's militias, which called themselves "anti-Balaka" -- meaning "anti-machete" -- formed in reaction to the takeover of the capital, Bangui, by the Seleka.
Mokom had denied involvement in the bloodshed, telling ICC judges in August m that he was "dedicated to the search for peace".
His lawyers said Mokom was tried in absentia in a case heard in Bangui "after the ICC confirmation of charges hearing".
"Neither Mr Mokom nor his lawyers were informed about this 'trial', despite everyone knowing that he was detained in The Hague," his lawyers said.
A two-page judgment in Bangui is said to have condemned Mokom to life in prison with forced labour, while his goods were confiscated and given to the state, in what his lawyers termed "an opportunistic political attack".
The CAR remains troubled and peace agreements signed in 2017 and 2019 have not been respected on the ground.
Set up in 2002, the ICC is the world's only independent tribunal capable of prosecuting those accused of the world's worst crimes.